What some idiots say if they start saying "FUCK" then realize they shouldn't and try to say crap, but it ends up making them sound like a bit of a derp.
As always, one catchy rap based phrase begets spin-offs. If crunk is a combination of crazy and drunk, figureing out the definition of fucrunk shouldn't be too hard.
If it is too hard then simply it means
f*#kin' crazy drunk
A group of fuck boys who hang out every damn day and vape with each other because they're to soft to smoke some goddamn weed. They act like little douche bags on snapchat and blow clouds into the camera. They post photos of themselves on instagram with some fucked up hair and squinty eyes tryna look all sexy so that some stupid thots will dm them or some shit. They typically speak in Ebonics because they think it sounds cool, even though they were not naturally raised to speak in such a manner.